Magnesium supplements against muscle cramps are a long time insider’s tip among runners. But do they really help?
Most runners have experienced it at some point or another: you merrily run along and suddenly there is a pain in your lower leg that feels like the muscle attempts to bend the shin bone into a u-shape and then jump out and live on its own.
If you are lucky, you and your rock-hard calf manage to hobble somewhere you can sit down. If you are unlucky, you fall, adding injury next to injury.
When you later tell fellow runners about your plight, you are likely to get one tip: you should have had a magnesium supplement. This supposedly prevents cramps from happening due to magnesium being responsible for communication between nerves and muscles.
No Solid Evidence For Magnesium
That sounds plausible and having had a cramp the other day myself, I finally had some keen interest in finding out if paying for a magnesium supplement is worth the money.
My first stop was the German Neurological Society’s website, that happened to have a guideline about treating cramps (PDF, German language). It states that magnesium supplements should be considered.
Case solved? Not really. Because the reason for their recommendation is not solid evidence about magnesium working. It’s rather a lack of any safe alternative form of treatment and magnesium has little to no side effects (beside diarrhea) when you take it in “normal” doses.
A bit disheartened I looked for the science behind their position. My second stop was therefore a meta-analysis of studies on treating muscle cramps with magnesium. It comes to the conclusion that the relation is poorly studied, but that already existing studies found no connection.
As the Cochrane Library is the gold standard of high-quality research, I gave up.
Quinine And Electrolytes?
The German society’s only other recommendation is the naturally occurring compound quinine, but only as a last line of defense. Here too usefulness is doubtful, but the side effects severe enough that the FDA put out a warning.
Once more a “natural” treatment isn’t necessarily risk-free. For me that puts it off the list of treating a very unpleasant, but hardly life-threatening problem.
Equally useless was examining a lack of electrolytes or fluids. Cramps happen independently of both, a South African review found (PDF).
What To Do?
As giving magnesium a shot isn’t very costly and only bears little risk, you may want to go ahead and see if it does something for you. Other than that I found it helps to slowly stretch the cramped muscle or to stress its antagonist. For the quadriceps, for example, that’s the hamstrings, for the calf (gastrocnemius) it’s the shin muscle (tibialis anterior).
How do you treat muscle cramps? Or did you try magnesium and had (no) success with it? Maybe you did something completely different. Please add your experiences in the comments!
Picture courtesy of Josiah Mackenzie.